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Finding the Fourth Proportional to 458.10, 687.15 and 318.90

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Solution

The fourth proportional to 458.10, 687.15 and 318.90 is: 478.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.10 : 687.15 = 318.90 : x
  2. Step 2: Convert to fraction form
    458.10/687.15 = 318.90/x
  3. Step 3: Cross multiply
    458.10x = 687.15 × 318.90
  4. Step 4: Simplify right side
    458.10x = 219,132.14
  5. Step 5: Solve for x
    x = 219,132.14/458.10
  6. Step 6: Final answer
    x = 478.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.